Multicenter evaluation of a new 4th generation HIV screening assay Elecsys HIV combi

Fourth-generation screening assays which permit a simultaneous detection of human immunodeficiency virus (HIV) antigen and antibody reduce the diagnostic window on average by four days in comparison to third-generation antibody assays. Recently, the new automated Elecsys HIV combi was compared in a multicenter study to alternative fourth- and third-generation assays, p24 antigen test and HIV-1 RNA RT-PCR. A total of 104 serocon-version panels, samples of the acute phase of infection after seroconversion (n = 33), anti-HIV-1 positive specimens (n = 572) from patients in different stages of the disease, 535 subtyped samples from different geographical locations, including group M (subtypes A-J) and group O, anti-HIV-2 positive sera (n = 364), dilutions of cell culture supernatants (n = 60) infected with different HIV-1 subtypes, selected performance panels, 8406 unselected samples from blood donors originating from different blood transfusion centers, 3810 unselected sera from daily routine and from hospitalized patients, 9927 unselected samples from South Africa and 1943 potentially interfering samples were tested with the Elecsys HIV combi. Elecsys HIV combi showed a comparable sensitivity to HIV-1 Ag stand-alone assays for early detection of HIV infection in seroconversion panels. The mean time delay of Elecsys HIV combi (last negative sample + 1 day) in comparison to HIV-1 RT-PCR for 92 panels tested with both methods was 3.23 days. The diagnostic window was reduced with Elecsys HIV combi between 1.56 and 5.32 days in comparison to third-generation assays. The specificity of Elecsys HIV combi in blood donors was 99.80% after repeated testing. Our results show that a fourth-generation assay with improved specificity and sensitivity like the Elecsys HIV combi is suitable for blood donor screening due to its low number of false positives and since it detects HIV p24 antigen with a comparable sensitivity to single antigen assays.

Effect of immediate neonatal zidovudine on prevention of vertical transmission of human immunodeficiency virus type 1

OBJECTIVE

To describe the effects of various short zidovudine (ZDV) prophylactic regimens on vertical transmission of human immunodeficiency virus type 1 (HIV-I) infection, especially the effect of immediate neonatal ZDV prophylaxis.

MATERIALS AND METHODS

The study included children of HIV-1-infected mothers who were born at a teaching hospital in Bangkok. The ZDV prophylaxis regimens varied by time periods that included: (1) no ZDV (1991-1996); (2) antenatal oral ZDV, 250 mg given twice a day starting at 34 to 36 weeks gestation and continued until labor (1995-1998); (3) antenatal oral ZDV plus immediate neonatal oral ZDV, 6 mg/0.6 mL/dose started within the first 2 hours after birth and continued at 6-hour intervals for 4 to 6 weeks (1997-1998); and (4) intrapartum intravenous ZDV given in addition to regimen 3 (1998-1999). Neonatal ZDV was administered within 2 hours after birth in 95% of the neonates.

RESULTS

In a cohort of 136 children born at least 9 months before the analysis date, the HIV-1 vertical infection rates were: (1) no ZDV, 11 of 48 (22.9%, 95% confidence interval [CI] = 12.0-37.3); (2) late antenatal ZDV, 10 of 47 (21.3%, 95% CI = 10.7-35.7); (3) late antenatal ZDV plus immediate neonatal ZDV, 0 of 28 (0%, 95% CI = 0-12.3); (4) late antenatal, intrapartum intravenous ZDV, plus immediate neonatal ZDV, 0 of 13 (0%, 95% CI = 0-24.7). An estimated 0% (95% CI = 0-8.6) of the infants who received immediate neonatal ZDV with or without intrapartum ZDV were infected, as compared with 22.1% (95% CI = 14.2-31.8 ) of those who received no ZDV or only late antenatal ZDV (P < 0.001).

CONCLUSIONS

The results of this study suggests high protective effect of immediate administration of neonatal ZDV. Perinatal components of antiretroviral prophylaxis provided the best results for protecting against vertical HIV-1 transmission.

Semiquantitative human immunodeficiency virus antibody tests in diagnosis of vertical infection

OBJECTIVE

This study evaluated the roles of semiquantitative anti-HIV antibody tests for early diagnosis of vertical HIV-1 infection in infants.

METHODS

The study included 0- to 18-month-old children of HIV-1-infected mothers. They were regularly followed up, and blood was obtained for semiquantitative anti-HIV tests using a particle agglutination (PA) test and a microparticle enzyme immunoassay (MEIA).

RESULTS

One hundred forty-six children of HIV-1-infected mothers, including 104 infected and 42 uninfected infants, were studied. Using anti-HIV titer of < or = 1:100 by PA and optical values of < or = -3 by MEIA for diagnosis of not being infected, approximately 69 and 53% of the uninfected cases at age 7 to 8 months, 76 and 67% at age 9 months and 100% at age 12 months could be diagnosed. By comparison with the diagnosis by qualitative tests the figures were 16%, 8 and 11%, 70 and 74% at the same ages. All asymptomatic HIV-infected cases had persistently high PA titers and MEIA values of at least 1:5000 and 6, respectively, but 7 cases with AIDS-related manifestation at the time of tests had low anti-HIV titers. One severely ill, HIV-infected infant had a transient negative anti-HIV test at the age of 7 months. Two asymptomatic infected children, who had been breast-fed, had transient decrease in anti-HIV titers after the age of 6 months, and transient seroreversion occurred in one. CONCLUSION. Semiquantitative anti-HIV tests between the age of 6 to 12 months were very useful in diagnosis of HIV-1 infection in infants born of HIV-1-infected mothers. Interpretation must be accompanied by information about AIDS-related manifestation and history of breast-feeding.

Serum C-reactive protein level in postsplenectomized thalassemic patients

C-reactive protein is an established marker for the detection of acute and chronic inflammatory processes. The most potent stimulator for the hepatic synthesis of this protein is interleukin 6. Previous studies have shown that inflammatory cells and inflammatory cytokines, such as interleukin 6, interferon gamma, etc were elevated in postsplenectomized thalassemic patients. The aim of this study was to determine serum C-reactive protein concentration in postsplenectomized beta thalassemic patients (beta thal/HbE postsplenec), and to compare them with those in nonsplenectomized beta thalassemic patients (beta thal/HbE), postsplenectomized non thalassemic patients (postsplenec), reactive thrombocytosis (RT), chronic myeloproliferative disorders (MPD) and normal adult volunteers. Serum C-reactive protein concentration as determined by an automatic Behring Nephelometer was carried out in 28 beta thal/HbE postsplenec, 22 beta thal/HbE, 12 postsplenec, 23 RT, 21 MPD, and 26 healthy adult volunteers. The values of CRP in beta thal/HbE postsplenec were significantly higher when compared with beta thal/HbE, and normal volunteers (4.1 +/- 0.7 vs 1.6 +/- 0.4 mg/L P = 0.006, and 4.1 +/- 0.7 vs 0.45 +/- 0.09 mg/L, P < 0.001). CRP levels in beta thal/HbE postsplenec were also higher than the postsplenec group (4.1 +/- 0.7 vs 0.19 +/- 0.7 mg/L P = 0.095). On the contrary, they were significantly lower than those in RT (4.1 +/- 0.7 vs 55.4 +/- 14.8 mg/L, P = 0.002). However, when compared to those with MPD, the values were not statistically different (4.1 +/- 0.7 vs 17.1 +/- 12.3 mg/L, P = 0.871). Interestingly, there was a trend towards increasing C-reactive protein levels in beta thal/HbE postsplenec patients with higher platelet count, although no correlation was observed. Besides the inflammatory process, platelet and/or factor(s) that control(s) thrombopoiesis seem(s) to play a role in the high serum C-reactive protein levels in the studied population.

Iron stores in autologous blood donors

Depletion of body iron stores is a major factor limiting regular blood donation in volunteer donors. Autologous blood donors are requested to donate more frequently. To determine iron stores in autologous donors, 9 men and 10 women studied gave a total of 24 donations before their elective surgery (range 1-2 donations). All donors were tested for serum ferritin (SF) and hemoglobin (Hb) level. Iron supplements were taken by 88.89 per cent of men and 90 per cent of women. Mean SF before donations was 147.75 ng/mL in men and 53.19 ng/mL in women. After donations, mean SF decreased to 124.26 ng/mL in men and 38.81 ng/mL in women. None of them had depleted iron stores (SF < or = 15 ng/mL). In conclusion, iron supplementation was beneficial in maintaining body iron stores in autologous blood donors.

Iron stores in Thai blood donors

A high number of blood donations may cause iron depletion. In order to evaluate iron stores in volunteer Thai blood donors, 82 male and 72 female donors were studied. All were tested for serum ferritin (SF), hemoglobin (Hb) level and asked for detailed histories of donations and iron supplementation. Mean SF in first-time donors was 161.12 ng/mL in men (n = 16) and 53.92 ng/mL in women (n = 23). Mean SF in multiple-time donors was 52.72 ng/mL in men (n = 66) and 25.72 ng/mL in women (n = 49). Depleted iron stores (SF < or = 15 ng/mL) were found in 8.7 per cent of first-time female donors, 21.21 per cent and 32.65 per cent of multiple-time male and female donors, respectively. The mean numbers of total donation were 51.42 +/- 30.8 in men and 8.22 +/- 6.97 in women. The estimation of depleted iron stores from Hb level could be determined in 57.14 per cent of male and 88.89 per cent of female donors. In conclusion, iron supplementation will benefit female donors and multiple-time male donors. The frequency of donations per year was more predictive of decreased iron stores than the number of total donations.

Effect of dialyzer membranes on beta-2 microglobulin production in Thai hemodialysis patients

Responses to different types of dialyzer membranes in an Asian population may differ from those of a Caucasian population. Comparative studies on the effects of different dialyzer membranes on beta-2 microglobulin production are also limited. Therefore, we conducted this study to determine the effects of different dialyzer membranes on in vitro mononuclear cell production of beta-2 microglobulin in 9 Thai hemodialysis patients. Each patient was dialysed with 4 different types of dialyzer, including cuprophane (CUP), cellulose diacetate (CD), polysulphone (PS), and polyacrylonitrile membrane (PAN), each for a 1-month period in a randomized sequence. Mononuclear cell culture was done by taking an immediate post-dialysis blood sample at the end of the 1-month period. Beta-2 microglobulin production from cell culture was determined 24 hours later. Mononuclear cell culture and determination of beta-2 microglobulin production from the culture were also done in 10 normal controls and 10 predialysis ESRD patients. The beta-2 microglobulin productions (microgram/L) were shown as follows; Control CUP CD PS PAN [table: see text] (*p < 0.05 compared to cuprophane membrane).

CONCLUSION

polysulphone and polyacrylonitrile membrane induced significantly less beta-2 microglobulin production compared to cuprophane and slightly less compared to cellulose diacetate membrane.